USB and LAN ports not working

just in case someone doesn't know how to take measurements properly... with an APOLOGY to those who can do it in their sleep.... not all of us have 50years experience in electronics and computing and even those of us who have that background.. it doesn't hurt to check your procedures once in a while.

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Board orientation... component side up, pcb track side down.

microUSB in bottom left corner... ethernet on right hand bottom corner... phono type (RCA) socket, video out on top edge in the middle, HDMI in middle of bottom edge.

connect power supply to microUSB socket S1 in bottom left corner of board.

test voltage with sd card inserted, video socket (RCA socket or HDMI) connected, keyboard connected to LOWER USB socket.

take test measurements with multimeter set to 10volt or 20volt (or nearest setting above 10volt) DC... on MOST meters this means black lead to COM socket, red lead to +V socket.

place point of black probe to TP2 (next to RCA (phono) video-out socket)

place point of red probe to TP1 (about an inch from the left side of the board and about 1/2inch from bottom of board)... its near the top of the small power regulator near the microUSB connector.

voltage should be above 4.5volt but NO MORE than about 5volts.

readings are ONLY relevant when powered on with all connections made.

a good psu, when measured at the psu connector but NOT connected to a circuit, may be as high as 7volts.

a poor (underpowered or faulty) psu might read 5volt when unconnected but 3volt or lower when fully connected as instructed.

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to ensure your Operating system is ok....... prepare and burn the SD card as directed by RaspberryPi.org or farnell or RS (personally I currently prefer RS instructions) then boot your normal computer or laptop from the SD card you just burned (most laptops etc have the ability... check your manual to boot from SD or how to alter bios)

if your SD image is ok, the computer will boot (even though you're using a raspberryPi version although your keyboard and mouse may have problems... DO NOT do any disk operations on the desktop or laptop... it MAY damage your hard drive.

if it DOESN'T boot, re-do the SD image (after re-booting normally)

I actual made 7 images using different operating systems (linux versions eg debian, fedora, ubuntu) and copying/formatting utilities BEFORE I got one to work properly.

a duff operating system SD card will NOT affect the above voltage readings.

General word of advice that applies whenever poking around a circuit with multimeter probes ...

At all costs, try to avoid holding two probes in place at the same time manually --- it's a recipe for tears.  Probes slip when we try to concentrate on two different points simultaneously, and the slightest slip can release the magic smoke that makes devices work.

Always look for a way to attach one probe (usually the ground reference) to the circuit in a stable fashion, so that you can focus all your attention on careful manual positioning of the other probe alone.  A few minutes spent securing your ground connection will pay back handsomely.  You will curse less and your blood pressure will thank you.

This also applies when your measurement is floating and so you can't use a ground reference, akthough it can be trickier to arrange then.  Nevertheless, aim to apply this advice in all cases, you won't regret it.  But you will regret not doing so one day, that's life.

General word of advice that applies whenever poking around a circuit with multimeter probes ...

At all costs, try to avoid holding two probes in place at the same time manually --- it's a recipe for tears.  Probes slip when we try to concentrate on two different points simultaneously, and the slightest slip can release the magic smoke that makes devices work.

Always look for a way to attach one probe (usually the ground reference) to the circuit in a stable fashion, so that you can focus all your attention on careful manual positioning of the other probe alone.  A few minutes spent securing your ground connection will pay back handsomely.  You will curse less and your blood pressure will thank you.

This also applies when your measurement is floating and so you can't use a ground reference, akthough it can be trickier to arrange then.  Nevertheless, aim to apply this advice in all cases, you won't regret it.  But you will regret not doing so one day, that's life.

and try not to touch more than one GPIO pin at the same time

with the same probe

coder27 wrote:

 

and try not to touch more than one GPIO pin at the same time

with the same probe

A version 2.0 of Pi really needs a female header.  Those open pins are just too inviting of shorts.

Of course, ideally there should be headers on two opposite edges of the board to provide physical support for daughterboards, but alas RPF seem more interesting in selling bespoke camera and display add-ons than in enthusiast-friendly design.